Reference front-matter in template#149

Insert front matter into templates using a format like {​{​ post.title }} or {​{​ blog.name }}

These attributes are now available:

{​{​ blog_title }}
{​{​ blog_description }} 
{​{​ blog_link }}
{​{​ blog_created_date }}
{​{​ blog_last_modified }} ago

{​{​ post_title }}
{​{​ post_description }}
{​{​ post_link }}
{​{​ post_published_date }}
{​{​ post_last_modified }} ago